Downhole apparatus

ABSTRACT

Apparatus for use in setting packers and other fluid actuated devices includes a tubular body (222), a valve (228) for controlling the flow of well fluid through a port (234) in the body (222) and a valve actuator (224) mounted on the body (222) and movable relative thereto, to open the valve (228) by application of well fluid pressure. The well fluid may flow through the open valve (228) to set a packer or actuate a device.

This invention relates to apparatus for use in downhole operations. Inparticular, but not exclusively, the apparatus is intended for use incompletion testing and in operations which take place immediatelyfollowing completion testing.

In the oil and gas exploration and extraction industries, deep bores aredrilled to gain access to hydrocarbon-bearing strata. The section ofbore which intersects this strata or "production zone" is typicallyprovided with a steel "liner", while the section of bore extending tothe surface is lined with steel "casing". Oil and gas is extracted fromthe production zone through production tubing extending through thecasing from the upper end of the liner. The production tubing is formedof a string of threaded sections or "subs" which are fed downwards fromthe surface, additional subs being added at the surface until the stringis of the desired length. As the string is assembled and fed into thebore its pressure integrity, or "completion", is tested at regularintervals. Such testing is also carried out on the complete string. Thetesting is accomplished by pressurising the internal bore of the string.Of course this requires that the string bore is sealed at its lower end.However, it is desirable that the string fills with well fluid as it islowered into the bore. The applicant has previously developed a tool toaccommodate these conflicting requirements, as described in GB-A-2 272774. The tool includes a sleeve mounted on a tubular body which formspart of the string. A port is provided in the body and is normallyaligned with a port in the sleeve to permit well fluid to flow, from theannulus, into the string. However, on pressurising the string bore, bypumping fluid down the bore from the surface, the resulting pressureforce acts on a piston defined by the sleeve to move the sleeve and sealthe body port. The completion of the string may then be tested. On thepressure being bled off, a spring returns the sleeve to the initialposition and opens the ports.

A string may carry a number of fluid pressure actuated tools orfittings, including packers for locating or sealing a production stringwithin a casing. Valves or plugs may also be provided on the lower endof the tubing and may be opened or removed once the packers have beenset, to permit formation testing and also to permit formation fluid toflow upwardly to the surface through the production tubing. Typically,packers are mounted on the exterior of the string and are inflated orotherwise set, when the packer is in the desired location, to engage thecasing. However, during completion testing any packers mounted on thestring may be prematurely set by the application of the elevatedcompletion testing pressures. Clearly this is not desirable, and maycreate difficulties as the string is moved downwardly and further intothe bore. Further, the opening or removal of valves or plugs followingsetting of the packers may require running in of an appropriate tool onwireline or coiled tubing, which will involve additional time andexpense.

It is among the objects of aspects of the present invention to obviateor mitigate one or more of these disadvantages.

According to the present invention there is provided downhole apparatuscomprising: a tubular body; a valve for controlling the flow of wellfluid through a first port in the tubular body, the port being incommunication with a fluid pressure actuated device; and a valveactuator mounted on the body and moveable relative thereto, to open thevalve, by application of well fluid pressure.

According to another aspect of the present invention there is provided amethod of selectively actuating a pressure actuated downhole tool, themethod comprising: providing a valve for controlling flow of well fluidthrough a port in a tubular body, the port being in communication with afluid pressure actuated device; providing a valve actuator on thetubular body; applying well fluid pressure to the actuator to open thevalve and permit communication of said fluid pressure to said device.

The invention thus provides a means for controlling actuation of fluidpressure actuated tools by well fluid pressurisation, thus obviating therequirement to provide control lines from the surface to the tools. Thetools may thus be located below packers and in other relativelyinaccessible locations.

Preferably, the actuator is movable in response to fluid pressureincreases and decreases within the tubular body. Typically, in use, themedium providing the fluid pressure will be fluid or "mud" being pumpedinto a tubing string from the surface. Most preferably, the actuatorincludes a member in the form of an axially slidable sleeve. The sleevemay be biassed towards a first position by spring means. In thepreferred embodiment, the sleeve defines a piston in fluid communicationwith the body bore, whereby an increase in bore pressure is communicatedto the piston and tends to move the piston towards a second position.

Preferably also, the actuator includes a ratchet assembly having amember which advances one step relative to the body towards a respectiveactuating position with each pressure cycle. Most preferably, theratchet assembly is provided between the body and the sleeve and anactuating member is advanced axially along the body. In the preferredembodiment the actuating member is located between respective ratchettracks defined by the sleeve and body.

The actuator sleeve may itself be a valve member and define a port forproviding communication with a further port in the body, to permitpassage of fluid between the interior of the body and the annulusdefined between the body and the bore wall. The apparatus may thus beutilised, in a first configuration, for completion testing in a similarmanner to that described in GB-A-2 272 774, and may then be utilised ina second configuration to open one or more valves for, for example,selective setting of packers or to open full flow ports in the string.The actuator sleeve may be initially positioned on the body to permitfluid communication through said further body port, application of fluidpressure to the actuator moving the sleeve to a second position to closethe port, means being provided for biasing the sleeve to return to theinitial position. In one embodiment, means is provided for restrictingreturn movement of the sleeve from the second position such that thefurther body port remains closed after a predetermined number ofpressure cycles.

The apparatus may include two or more valves for selectively controllingfluid communication to a plurality of respective tools and the like.

The valve may be in the form of a shuttle valve, or may include a valvesleeve or other valve member defining at least one port which may bealigned with the body port to permit fluid communication therethrough;in a first position the valve member closes the body port and is movableto a second position to allow flow through the body port. In a preferredembodiment, the valve member is movable beyond the second position to athird position to close the body port once more.

The apparatus may be provided in combination with one or more packers orwith a flow sleeve. The flow sleeve may be opened, following completiontesting and setting of the packers, to allow fluid to flow between thelower end of the string and the annulus. The flow sleeve may comprise atubular body with a port in the body wall, and an aperture sleevemounted on the body, the body port initially being closed by the sleeve.A pressure port provides fluid communication between the valve and apiston face defined by the sleeve, and on opening the valve the fluid inthe body bore may apply a pressure force to the sleeve and move thesleeve to a second position and open the body port. The sleeve may beretained in an initial position by releasable means, such as shear pins,and may be retained in the second position by a latch or ratchet.Biassing means, such as a spring, may also be provided to assist inmoving the sleeve to the second position. The end of the flow sleevebody is initially closed, preferably by a removable plug. Thus, when itis desired to fully open the lower end of the string, the plug may beremoved using, for example, wireline or coiled tubing provided with anappropriate fishing tool.

According to another aspect of the present invention there is provideddownhole apparatus comprising first and second parts initiallyreciprocally movable between first and second relative positions andwherein it is desired subsequently to restrict the relative reciprocalmovement of the parts, the apparatus further comprising a connectingmember being movable with the second part with each movement of thesecond part in one direction and being retained by the first part witheach subsequent movement of the second member in the opposite directionsuch that the connecting member position is advanced relative to thefirst part with each cycle, in a selected one or more of its positionsthe connecting member supporting a portion of the first part to engagewith a portion of second member to restrict the relative movementbetween the first and second parts.

The connecting member may initially be positioned relative to the firstmember to permit movement between the first and second positions andrestrict said movement on reaching a selected advanced position. Thus, afull degree of movement may be available for a predetermined number ofcycles and then only a restricted movement being available forsubsequent cycles.

In a preferred embodiment the apparatus incorporates a valve which isopen when the parts are in their first relative positions but is closedwhen the parts move to their second relative positions; initially theconnecting member permits the valve to be closed and opened, but in itsadvanced position the connecting member prevents the valve from opening.Such an apparatus may be utilised as a completion testing tool, forpermitting selective fluid communication between the tubing and annulus.

Preferably also, a ratchet link is provided for advancing the connectingmember, and the first and second parts define respective ratchet teeth,a ratch moving with the second part in said one direction and being heldrelative to the first part when the second part moves in said oppositedirection.

Preferably also, said portion of the first part includes a radiallymovable element and said portion of the second part includes a shoulder,the connecting member being located below the movable element anddefining a recessed surface which, in selected positions of theconnecting member, permits retraction of the movable element to clearthe shoulder. The movable element may be in the form of a spring finger,but is preferably in the form of a key located in a aperture in aportion of the first part.

This aspect of the invention may be combined with embodiments of thefirst aspect of the invention described above.

These and other aspects of the present invention will now be described,by way of example, with reference to the accompanying drawings, inwhich:

FIG. 1 is a somewhat schematic view of downhole apparatus in accordancewith a first embodiment of the present invention, including a completiontesting tool, two centralisers, a packer, and a full flow sleeve mountedon the end of a string;

FIG. 2 is an enlarged sectional view of the completion testing tool anda centraliser of FIG. 1;

FIG. 2A is a scrap view on arrow A of FIG. 2;

FIG. 3 is a representation of the ratchet profile of the completiontesting tool of FIG. 2;

FIG. 4 is an end view of a centraliser of FIG. 1;

FIG. 5 is a sectional view on line 5--5 of FIG. 4, illustrating a valvearrangement;

FIG. 6 is a sectional view on line 6--6 of FIG. 5, illustrating thevalve arrangement;

FIG. 7 is a sectional view of the valve arrangement of FIG. 5, showingthe valve arrangement in the open position;

FIG. 8 is a somewhat enlarged sectional view of the full flow sleeve ofFIG. 1;

FIGS. 9A-9D are somewhat schematic illustrations of apparatus inaccordance with a preferred embodiment of the present invention;

FIG. 10 is a sectional view of a multicycle tool of the apparatus ofFIG. 9;

FIG. 11 is an enlarged sectional view of valves provided in the tool ofFIG. 10;

FIGS. 12, 13, 14 and 15 are half sectional views of a portion of amulticycle tool in accordance with a further embodiment of the presentinvention; and

FIG. 16 is a sectional view of a portion of a tool in accordance withanother embodiment of the present invention.

Reference is first made to FIG. 1 of the drawings which illustratesdownhole apparatus in accordance with a first embodiment of the presentinvention. The apparatus includes a completion testing tool 10, twocentralisers 12,13, a packer 14, and a full flow sleeve 16. In thisexample, the apparatus 10 is mounted on the lower end of a tubularproduction string 18. As will be described, the completion test tool 10is utilised as the string is extended into a bore lined with casing. Atintervals the pressure integrity or "completion" of the string is testedusing the tool 10. Once the string 18 has been made up to its fulllength and has been fully tested, the tool 10 is configured to allowsetting of the packer 14. Following setting of the packer 14, the tool10 is re-configured to allow opening of the sleeve 16.

Reference is now made to FIG. 2 of the drawings which illustrates, insomewhat schematic fashion, the completion test tool 10 and the uppercentraliser 12. The tool comprises a tubular body 20 defining a bore 22which forms a continuation of the string bore. Mounted on the body 20 isan actuator in the form of a sleeve 24.

Both the body 20 and the sleeve 24 define flow ports 26,28 which arenormally aligned to allow fluid to flow from the annulus between thesleeve 24 and the bore casing into the bore 22. Appropriate O-rings orS-seals are provided above and below the ports. Movement of the sleeve24 relative to the body 22 is controlled by a ratchet 29 including aprofile 30 (see FIG. 3) defined on an inner face of the body 20 and afollower 32 extending from the sleeve 24. Both FIGS. 2 and 3 illustratethe follower 32 in an initial position engaging a first stop 33. Thisinitial position, with the ports 26,28 aligned, is maintained by aspring 34 which biases the sleeve 24 downwardly relative to the body 20.

As the string 18 is run-in, the aligned ports 26,28 allow well fluid toflow into the string bore. However, when it is desired to test thecompletion of the string, mud pumps at the surface are started and pumpfluid into the bore. The pumped flow of fluid cannot be accommodated bythe aligned ports 26,28 such that the fluid pressure within the borerises. This pressure acts upon an annular piston 36 defined on an innerface of the sleeve 24 and in communication with the bore 22 via pistonports 38. Thus, the sleeve 24 is pushed upwardly relative to the body20. This relative movement results in the ports 26,28 becomingmisaligned such that the body ports 26 are blanked off by the sleeve 24.The string bore is now sealed, and by monitoring the fluid pressure inthe bore at the surface, the completion of the string may be confirmed.The position of the follower 32 on the profile 30 at this point,engaging the second stop 42, is shown in FIG. 3.

Bleeding off pressure from the bore allows the spring 34 to move thesleeve downwardly once more though, due to the offset of the profilepeak 40 from the stop 42, the follower 32 does not return to the stop 33and the sleeve 24 is forced to rotate on the body 20 as it returns toits initial longitudinal position, with the follower 32 engaging a stop43 aligned with the first stop 33. Of course, this requires that ports26,28 are provided around the circumference of one or both of the body20 and sleeve 24 to ensure that there are ports 26,28 in alignment afterrotation of the sleeve 24 on the body 20.

The profile illustrated in FIG. 3 provides for the completion of thestring to be tested on up to three separate occasions, though of coursethe profile could be configured to provide a smaller or greater numberof testing opportunities. Typically, two completion tests are carriedout, with a "spare" test position being available if necessary. In othercases additional "spare" test positions may be provided. However, onpressurising the string bore for a fourth time, the follower moves fromthe stop 46, aligned with the stop 33 and 43, to an opposing stop 48which permits a greater degree of relative longitudinal movement betweenthe sleeve 24 and the body 20 than the stop 42, allowing the sleeve 24to move to a second longitudinal position. As will be described, thisre-configuring of the sleeve 24 on the body 20 allows opening of a valveprovided in the centraliser 12, to allow setting of the packer 14. Onbleeding pressure off from the bore, the follower 32 travels to afurther stop 50 which allows for a greater degree of downward movementof the sleeve 24 on the body 20 than provided by the stops 33,43,46. Inthis further configuration the sleeve 24 is used to open a valveprovided in the centraliser 13 to allow opening of the sleeve 16, aswill be described.

Reference is now also made to FIG. 4 of the drawings which is an endview of the centraliser 12 and shows a pressure port 52 which providesselective fluid communication, via a valve arrangement 54, as shown inFIG. 2 and as illustrated in FIGS. 5, 6 and 7 of the drawings, with aport 56 in communication with the string bore.

The valve arrangement 54 includes a cylindrical body 58 and a plunger orrod 60 extending from one end of the body 58, both being located withina longitudinally extending valve chamber 62 defined by the centraliser12. The body 58 carries two spaced seals 64,65 which, with the valveclosed, isolate the string bore communicating port 56 from the pressureport 52. The free end of the rod extends from the open lower end of thechamber 62. The body and rod 58,60 are initially restrained againstmovement by a shear out circlip 68 mounted on the end of the rod 60extending from the chamber 62 and abutting the centraliser lower face.

The pressure port 52 is connected to a fluid line 70 (FIG. 1) whichleads to the packer 14. To set the packer 14, the valve 54 is openedallowing pressurised fluid from the bore to flow in through the port 56,through the valve arrangement 54, and then from the pressure port 52into the packer 14. The valve 54 is opened by an actuation dog 72 on theupper end of the sleeve 24 (see FIGS. 2 and 2A) pushing the rod 60upwardly. However, the dog 72 only contacts the end of the rod 60 as thesleeve 24 is lifted relative to the body 20 and the follower 32 contactsthe profile stop 48 which, as noted above, permits a greater degree ofupward movement of the sleeve 24 than the earlier stops 42. Thus, thesleeve 24 only moves sufficiently to contact the rod 60 on its fourthpressure cycle, and typically after two completion testing operationsand a further pressure cycle.

On the packer being correctly set, a hydraulic piston or other movingpart within the packer 14 reaches the end of its travel and contacts atransmitter switch, causing a transmitter on the packer 14 to transmit asignal, typically a "ping", which may be detected at the surface. Thisinforms the operator that the packer has been set. Where a number ofpackers are provided, each may include a transmitter which transmits adifferent frequency signal, allowing the operator to determine whichpackers have been set.

The lower centraliser 13 is similar to the upper centraliser 12described above and may be configured to allow fluid from the stringbore to flow into and actuate the full flow sleeve 16, as will now bedescribed with reference to FIG. 8 of the drawings. The sleeve 16 has abody 76 forming the lower end of the string and defining a through bore78, though initially the lower end of the bore 78 is sealed by aremovable plug 80. The body wall defines a number of ports 84 which areinitially blanked off by a sleeve 86, movably mounted over the body 76.The sleeve defines a number of ports 88 which, as will be described, maybe aligned with the body ports 84 to allow flow of fluid between thestring bore and the annulus. Appropriate O-rings or S-seals are providedabove and below the ports 88.

The sleeve 86 is biased towards the position in which the ports 84,88are aligned by a spring 95, but is initially held on the body by shearpins 90 such that the ports are mis-aligned. To move the sleeve 86 andalign the ports 84,88, pressure is applied through pressure port 82,which communicates with the pressure port 52 of the centraliser 13. Thepressure force exerted by the fluid acts on an annular piston 94defining the lower wall of a spring chamber in the sleeve 86, to shearthe pins 90, and allowing the spring 95 to push the sleeve 86 downwardlyrelative to the body 76. A latch arrangement 96 is provided between thebody 76 and the sleeve 86 to prevent retraction of the sleeve 86 oncethe ports 84,88 have been aligned, and a guide pin 97 ensures properalignment of the sleeve 86 on the body 76.

The valve in the centraliser 13, which allows fluid to flow from thestring bore into the port 92, is actuated by a dog 98 on the lower endof the sleeve 24 (see FIG. 1). The dog 98 contacts the centraliser valverod 60 only when the follower 32 moves towards the stop 50 of theprofile 30 (see FIG. 3), which permits a greater degree of downwardmovement of the sleeve 24 than the earlier stops 33,43,46.

This additional movement of the sleeve 24 closes the ports 26,28 and thepiston ports 38, to allow the string bore to be pressurised. Also, theposition of the next stop 51 on the profile 30 prevents subsequentupward movement of the sleeve 24 to the extent necessary to realign thebores 26,28, and thus effectively latches the sleeve 24 in the closedposition.

The plug 80 may remain in place until it is necessary to provideunrestricted passage through the string bore. The plug 80 is supportedagainst downward movement by a bore restriction 100, to prevent the plug80 being pushed from the body 76 by completion testing pressures withinthe bore, and shear pins 101 prevent upward movement. The plug defines atest port 104. To remove the plug 80 from the bore 78 it is simplynecessary to lower a suitable fishing tool on coiled tubing to engagethe plug fishing neck 102 and then pull upwardly to shear the pins 101.The plug 80 may thus be withdrawn from the bore 78.

Reference is now made to FIG. 9 of the drawings, which illustratesapparatus in accordance with a preferred embodiment of the presentinvention. The apparatus 200 is shown located towards the lower end of aborehole and is mounted on the lower end of a tubing test string 202made up of a number of threaded tubular lengths. The borehole is linedwith casing 204 and at the lower end of the borehole, which intersectsan oil bearing formation, a liner 206 is provided and is mountedrelative to the casing 204 by a liner seal 208. In this embodiment theapparatus 200 comprises a multicycle tool 210, a completion test tool212, an isolation valve 214 and an inflatable packer, the valve 214 andpacker 216 being coupled to the tool 210 by respective control lines215, 217 216.

Before describing the elements of the apparatus 200 and their operationin detail, the mode of use of the apparatus 202 will be brieflydescribed.

As the string 202 is made up and lowered into the borehole, with theapparatus 200 on the lower end thereof, the isolation valve 214 islocked shut while the completion test tool is normally open, allowingwell fluid to fill the string 202. Tubular or sections are added to thestring 202 at the surface until a collet 218 provided on the lower endof the string 202 engages the liner top, thus providing an indication atthe surface of length of string necessary to properly locate the end ofthe string in the liner 206. The tubing string 202 may then be retractedsomewhat to cushion as required (FIG. 9A).

The completion test tool 212 is then closed or locked out by pumpingwell fluid into the string 202 above a predetermined rate, as disclosedin the above-mentioned UK Patent Application. As will be described, themulticycle tool 210 operates in conjunction with the completion testtool 212 to lock the tool 212 in its closed configuration (FIG. 9B).

The string is then spaced out and the tubing hanger and downhole safetyvalve (not shown) are pressure tested. After a number of additionalpressure cycles are applied to the string 202 to cycle the tool 210 toallow for equipment or testing problems the packer 216 is set usingpressurised well fluid from the string bore. Application of a furtherpressure cycle operates the tool 210 to allow opening of the isolationvalve 214.

Reference is now also made to FIG. 10 of the drawings, which is asectional view of the multicycle tool 210. The upper half of the drawingshows the tool in a first configuration and the lower half of thedrawing shows the tool in a second configuration, when hydraulic fluidpressure above a predetermined level is being applied to the stringbore.

The tool 210 comprises a tubular body 222 and a sleeve 224 mounted onthe body 222 and being movable in a reciprocal manner relative theretoby cyclic application of fluid pressure, as will be described. Fouractuators (only two shown) including actuator members in the form ofratches 226, 227 are provided for opening valves on the upper end of thebody 222, in this particular embodiment the actuator serving to openrespective shuttle valves 228, 229, as will be described.

The body 222 defines two series of fluid ports, the first ports 230 forcommunicating with a piston area 232 defined by a shoulder on the sleeve224, and the second set of ports 234 for communicating with therespective valves 228, 229.

The sleeve 224 is retained on the body 222 between an end cap 236 and anend sleeve 238 which accommodates the valves 228, 229. The sleeve 224 isnormally biased upwardly by a compression spring 240 acting between theend cap 236 and a shoulder 242 defined by the sleeve 224.

The upper end of the sleeve 224 defines four axially extending ratchettracks 244, 245 (only two shown) located adjacent respective ratchettracks 246, 247 defined on the outer surface of the body 222. Theratches 226, 227 are located between the respective tracks 244-247.

Application of fluid pressure above a predetermined level to the bore ofthe body 222 creates sufficient force on the piston area 232 to overcomethe spring 240 and move the sleeve 224 downwardly relative to the body222, to the configuration as illustrated in the lower half of FIG. 10.During this movement of the sleeve 224, the ratches 226, 227 arerestrained axially relative to the body 222 by the body ratchet tracks246, 247. The teeth of the sleeve ratchet tracks 244, 245 are spacedapart such that the upwardly adjacent tooth passes under the lower edgeof the respective ratches 226, 227, such that when pressure is bled offfrom the string bore the ratches 226, 227 will move upwardly with thesleeve 224, as the sleeve 224 is returned to its initial position underthe action of the spring 240.

Each ratch comprises an inner part 248 for engaging the sleeve ratchettracks 244, 245 and an outer part 250 for engaging the body ratchettracks 245, 246. A compression spring 252 between the parts 248, 250pushes the parts radially apart and into contact with the respectivetracks. The assemblies 226, 227 are generally trapezoidal in section.

It will be noted that each pressure cycle will advance the respectiveratch 226, 227 one step up the respective body ratchet track 246, 247.When moving onto the uppermost step of the tracks 246, 247, the assembly226, 227 engages the lower end of a valve shuttle 254, 255. Details ofthe shuttles 254, 255, and the shuttle valves 228, 229, may be seen inFIG. 11 of the drawings, the upper half of the drawings showing theshuttle 254 in the closed position, and the lower half of the drawingshowing the shuttle 255 in the open position. Each shuttle 254, 255 isbiased towards the closed position by a respective compression spring256 and controls fluid communication between the respective body ports234 and ports 258, 259 leading to respective control lines incommunication with the completion test tool 212, isolation valve 214 andpacker 216.

The number of pressure cycles necessary to open a respective shuttlevalve 228, 229, and thus permit pressure actuation of the respectivetool 212, 214, 216, is determined by the initial positioning of therespective ratches 226, 227 on the ratchet tracks 244-247; four pressurecycles will be necessary to bring the ratch 226 illustrated in FIG. 10into contact with the shuttle 254, whereas if the ratchet assembly 226had initially been located further up the ratchet tracks fewer pressurecycles would have been required.

As noted above, the completion test tool 212 provided in conjunctionwith the multicycle tool 210 is similar to that described inGB-A-2272774, with the addition of a locking sleeve which may be movedinto a position to lock the tool closed. The locking sleeve is movedinto the locking position by application of fluid pressure to the tubingbore, and is moved into locking position after a predetermined number ofpressure cycles under the control of the multicycle tool 210.

Further pressure cycles will cause a second ratch to move a respectiveshuttle to the open position, allowing inflation of the packer 216 viathe multicycle tool 210.

Further pressure cycles will then cause a third ratch to move arespective shuttle to the open position, allowing opening of theisolation valve 214 by application of well fluid pressure.

Reference is now made to FIGS. 12, 13, 14 and 15 of the drawings, whichillustrate a portion of a tool 310 in accordance with a furtherembodiment of the present invention. The tool 310 comprises a first partin the form of a tubular body 322 and a second part in the form of asleeve 324 being mounted on the body 322 and being movable in areciprocal manner relative thereto by cyclic application of fluidpressure, in a similar manner to the embodiments described above.Further, the tool 310 includes an actuator of similar form to theactuator of the tool 210, including an actuator member in the form of aratch 326 which is advanced along a ratchet track by movement of thesleeve 324 relative to the body 322.

The tool 310 acts as a completion test tool in a similar manner to thetools described above: in an initial normal position the body 322 andsleeve 324 define aligned bores (not shown) which permit fluidcommunication between the body bore and the annulus. However, byincreasing the fluid pressure in the body bore the sleeve 324 may bemoved relative to the body 322, to close the body port.

The ratch 326 engages an end of a sleeve 325 which forms a valve member.The sleeve 325 defines a port 327 which may be aligned with a port 334in the body 322 to provide communication with a bore 335 formed on anouter portion of the body 337 and which communicates with a fluidpassage connectable to a control line extending to a packer.

A feature of the tool 310 is that the return movement of the sleeve 324relative to the body 322 is restricted such that after a predeterminednumber of pressure cycles the sleeve 324 will be restrained relative tothe body 322 such that the ports for providing fluid communicationbetween the body bore and the annulus do not come into alignment. Theouter body portion 337 defines a male part 339 which is received by afemale part 341 of the sleeve 324 as the sleeve 324 moves upwardlyrelatively to the body 322. The male part 339 defines an aperture 343locating a key in the form of a ball 345. The initial normal relativepositions of the body 322 and the sleeve 324 are illustrated in FIG. 12,from which it will be noted that the ball 345 has been deflectedradially inwardly, by contact with the inner wall of the female part341, into an annular recess 347 defined in the outer wall of the sleeve325. On the pressure within the body bore being increased, the sleeve324 moves upwardly, carrying the ratch 326, such that the sleeve 325advances along the body 322. With the sleeve 325 positioned relative tothe body 322 as illustrated in FIG. 12, on bleeding-off the pressurefrom the body bore the female part 341 of the sleeve is free to moveover the male part 339 of the body 322. However, as the valve sleeve 325is moved upwardly relative to the body 322 in a subsequent pressurecycle, the ball 345 is moved radially outwardly from the recess 347 andextends into a recessed portion 349 of the sleeve 324. When pressure isthen bled-off from the body bore, the sleeve 324 moves downwardly onlyuntil a shoulder 351 defined at the upper end of the recess portion 349contacts the ball 345 (FIG. 13A). As the ball 345 is no longer free tomove radially inwardly further movement of the sleeve 324 is prevented,and thus the apertures in the body 322 and sleeve 324 remain out ofalignment.

In subsequent pressure cycling, the sleeve 324 will of course only movea restricted distance relative to the body 322, and this is accommodatedby the provision of smaller teeth on the ratchet tracks 344, 346.

It will also be noted that, in this embodiment, continued pressurecycling will align the ports 327, 334 allowing fluid communication withthe packer (FIG. 14), and a further cycle will move the valve sleeve 325to seal the port 334 (FIG. 15).

This embodiment of the invention features a further feature not presentin the other embodiments, which allows the position of the valve sleeve325 to be monitored from the surface. This is useful in that it providesan indication of, for example, the number of cycles that are availablebefore the sleeve 324 is restrained by the ball 345 contacting theshoulder 351, or the number of cycles before the packer is set. Thevalve sleeve 325 is provided with a copper insert 352 which, as it ismoved up the body 322, contacts small transmitters 353, 355, 357provided in the body, and triggers the transmitters to produce a signalat a predetermined frequency. The signals are detected and displayed atthe surface using a suitable receiver and display apparatus, and thusprovide the operator with an indication of the position of the valvesleeve 325. This feature is useful as movement of the string in the boreduring make-up may inadvertently result in movement of the actuatorsleeve 324 and advance the ratch 326 along the track 346; if theoperator is unaware of this it is possible that, for example, the packerwould be actuated prematurely.

Reference is now made to FIG. 16 of the drawings, which illustrates aportion of the tool 410 in accordance with another embodiment of presentinvention. In the previously described embodiments, the tools werearranged to provide selective fluid communication with further tools onthe string. However, the tool 410 includes a valve arrangement forcontrolling the supply of pressurised bore fluid to a single fluidactuated device forming part of the same tool. The tool 410 includes aratch 426 which may be advanced along a ratchet track 446 on the toolbody 422 from an initial position (see upper half of figure) to open avalve (see lower half of figure) including a sleeve 425 defining apassage for providing fluid communication between the body bore and apassage 458 leading to the fluid actuated device.

It will be noted from the above described embodiments that theapparatuses provide a convenient arrangement for sequentially testingthe completion of a string, and then actuating or setting a variety oftools and devices, including packers, full flow sleeves and isolationvalves, merely by cycling the pressure of fluid in the string bore. Itwill be clear to those of skill in the art that the apparatus may beutilised in combination with a range of other tools.

What is claimed is:
 1. Downhole completion apparatus for mounting on astring below a packer in combination with a fluid pressure actuateddevice, the apparatus comprising:a tubular body defining a bore; meansfor sealing the body bore; a valve for controlling the flow of wellfluid through a first port in the tubular body, the port being incommunication with said fluid pressure actuated device; and a valveactuator mounted on the body and movable relative thereto, to open thevalve, on application of well fluid pressure to the body bore above thesealing means, to permit actuation of said fluid pressure actuateddevice.
 2. The apparatus of claim 1 wherein the actuator includes anaxially slidable sleeve, the sleeve being a valve member and defining acirculating port for selectively providing fluid communication with afurther port in the body, to permit fluid circulation between the boreand an annulus defined between the body and a surrounding bore wall. 3.The apparatus of claim 1 in which the fluid actuated device is a packer.4. The apparatus of claim 2 wherein the sleeve is biased towards a firstposition by a spring.
 5. The apparatus of claim 2 wherein the sleevedefines a piston in fluid communication with the body bore, whereby anincrease in the bore pressure is communicated to the piston and tends tomove the piston towards a second position.
 6. The apparatus of claim 2wherein the actuator sleeve is initially positioned on the body topermit circulation through said further body port, application of fluidpressure moving the sleeve to a second position to close the port, andmeans being provided for biasing the sleeve to return to the initialposition.
 7. The apparatus of claim 1 including two or more valves forselectively controlling well fluid communication to a plurality of fluidactuated devices.
 8. The apparatus of claim 1 in combination with one ofa flow sleeve and an isolation valve.
 9. Downhole apparatus for locationin a drilled bore, the apparatus comprising:a tubular body defining abore; a fluid pressure actuated device mounted on the body; a valve forcontrolling flow of well fluid through a first port in the tubular bodyto control actuation of the fluid pressure actuated device; and a valveactuator mounted on the body and movable relative thereto to open thevalve on application of well fluid pressure, the valve actuatorincluding an axially slidable sleeve defining a circulating port forselectively providing fluid communication with a further port in thebody, to permit passage of fluid between the body bore and an annulusdefined between the body and the wall of the drilled bore.
 10. Downholecompletion apparatus for mounting on a string below a packer, theapparatus comprising:a tubular body defining a bore; means for sealingthe body bore; a valve for controlling the flow of well fluid through afirst port in the tubular body, the port being in communication with afluid pressure actuated device; and a valve actuator mounted on the bodyand movable relative thereto, to open the valve, on application of wellfluid pressure to the body bore above the sealing means, the actuatorincluding an axially slidable sleeve, the sleeve being a valve memberand defining a circulating port for selectively providing fluidcommunication with a further port in the body, to permit fluidcirculation between the bore and an annulus defined between the body anda surrounding bore wall,the actuator sleeve being initially positionedon the body to permit circulation through said further body port,application of fluid pressure moving the sleeve to a second position toclose the port, and means being provided for biasing the sleeve toreturn to the initial position, wherein means is provided forrestricting return movement of the sleeve from the second position suchthat the further body port remains closed after a predetermined numberof pressure cycles.
 11. Downhole apparatus for location in a drilledbore, the apparatus comprising:a tubular body defining a bore; a fluidpressure actuated device mounted on the body; a valve for controllingflow of well fluid through a first port in the tubular body to controlactuation of the fluid pressure actuated device, the actuator includingan axially slidable sleeve, the sleeve being a valve member and defininga circulating port for selectively providing fluid communication with afurther port in the body, to permit fluid circulation between the boreand an annulus defined between the body and a surrounding bore wall,wherein the actuator includes a ratchet assembly having a ratch memberwhich advances one step relative to the body towards an actuatingposition with each pressure cycle.
 12. The apparatus of claim 11 whereinthe ratchet assembly is provided between the body and the sleeve and theratch member is advanced axially along the body.
 13. The apparatus ofclaim 12 wherein the ratch member is located between ratchet tracksdefined by the sleeve and body.
 14. Downhole completion apparatus formounting on a string below a packer, the apparatus comprising:a tubularbody defining a bore; means for sealing the body bore; a valve forcontrolling the flow of well fluid through a first port in the tubularbody, the port being in communication with a fluid pressure actuateddevice; and a valve actuator mounted on the body and movable relativethereto, to open the valve, on application of well fluid pressure to thebody bore above the sealing means, wherein the valve is in the form of ashuttle valve.
 15. A method of selectively actuating a pressure actuateddownhole device mounted on a tubular body defining a bore and mounted ona string below a packer, the method comprising:sealing the body borebelow the packer; providing a valve for controlling flow of well fluidthrough a port in the tubular body, the port being in communication witha fluid pressure actuated device; providing a valve actuator on thetubular body; and applying well fluid pressure to the body bore to movethe actuator to open the valve and permit communication of said fluidpressure to said device to actuate said device.
 16. The method of claim15 wherein the pressure actuated device is the packer and the packercommunicates with the port via a control line.
 17. The method of claim16 wherein the valve is located below the packer.
 18. A method of (i)selectively actuating a pressure actuated downhole device mounted on atubular body defining a bore and (ii) permitting fluid circulationbetween the body bore and an annulus defined between the body and thewall of a drilled bore, the method comprising:providing a valve forcontrolling flow of well fluid through a port in the tubular body, theport being in communication with a fluid pressure actuated device;providing a valve actuator on the tubular body, the valve actuatorincluding an axially slidable sleeve defining a circulating port forselectively providing fluid communication with a further port in thebody; (i) applying well fluid pressure to the actuator to open saidvalve and actuate said device; and (ii) applying well fluid pressure tothe actuator to move the sleeve and permit fluid circulation between thebody bore and an annulus defined between the body and the wall of thedrilled bore via said circulating port and said further port in thebody.